Hydraulic apparatus



Dec. 5, 1961 T. BUDZICH HYDRAULIC APPARATUS 3 Sheets-Sheet 1 Filed Jan.4, 1960 INVENTOR. TADEUSZ BUDZ ICH WA/%% AT TORNE Y Dec. 5, 1961 T.BUDZICH HYDRAULIC APPARATUS 5 Sheets-Sheet 2 Filed Jan. 4, 1960 V GIINVIENTOR. TADEUSZ BUDZICH A ATTORNEY Dec. 5, 1961 T. BUDZICH HYDRAULICAPPARATUS 5 Sheets-Sheet 3 Filed Jan. 4, 1960 INVENTOR. TA DEUSZ BUDZ/CHBY I ATTORNEY 3,011,453 HYDRAULIC APPARATUS V Tadeusz Budzich, 3344Colwyn Road, Cleveland 20, Ohio Filed Jan. 4, 1960, Ser. No. 129

17 Claims. (Cl. 103-173) The present invention relates to fluid pressureapparatus and more particularly to fluid pumps and motors of axialpiston type. In still more particular aspects the invention relates toaxial piston pumps and motors of the type having a stationary cylinderbarrel and employing a rotary cam plate and rotary valving means.

Both rotating and stationary cylinder barrel types of multi-piston axialpumps and motors are well known in the art. Both types have certaininherent advantages and disadvantages.

Hereto-fore the rotating cylinder barrel type has been characterized byhigh mechanical and volumetric efficiencies while working at relativelyhigh pressures and low rotational speeds. This is mainly due to aconstruction in which the cylinder barrel is capable of aligning itselfto a working face of a valve plate and there hydrostatically balancedwith minimum mechanical losses and operable with minimum leakage. Butthe rotating cylinder barrel has heretofore had serious disadvantagesbecause the rotating piston assemblies \are subjected to centrifugalforce. This not only increases the bearing pressure between each pistonand cylinder bore butproduces an unbalanced couple since, due to thereciprocating motion, the centers of gravity of the individual pistonassemblies are spaced longitudinally from each other while rotating.This disturbs the equilibrium of the cylinder bar-rel and results inloss of efiiciency. While these disturbing centrifugal effects are smallat low r.p.m., the disturbing influence is proportional to the speedsquared, so that at high rotational speeds they become quite serious andrequire that high unbalanced loads be carried on the face of the valveplate to prevent separation of cylinder barrel from valve plate. I 1

In the stationary cylinder barrel .type of multi-piston axial pumps andmotors the effect of increased bearing pressures (between piston andcylinders) and disturbing couples due to centrifugal effect arecompletely elimi- States Patent self-aligning cylinder barrel isstabilized by dynamic pads supporting the cylinder barrel around itsfull outer periphery.

Another object is to provide means biasing cylinder barrel and valveplate together for starting.

Other objects and advantages will become apparent and the invention maybe better understood from consideration of the following descriptiontaken in connection with the accompanying drawing, in which:

FIG. 1 is a longitudinal section view of a fluid pump or motor embodyingthe present invention; I FIG. 2 is a vertical section view taken on theline 2--2 of FIG. 1;

,. FIG. 3 shows end face of valve plate as viewed in the direction ofarrows 3-3 in FIG. 2, and

FIG. 4 shows end face of cylinder barrel as viewed in the direction ofthe' arrows 44 of FIG. 2.

FIG. 5 shows a modified arrangement of high pressure porting of a valveotherwise as in FIG. 2;

FIG. 6 shows end face of valve plate as viewed in the direction ofarrows 6-6 in FIG. 5 and FIG. 7 is a diagrammatic illustration of theprinciple of suspending cylinder barrel in accordance with one aspect ofthe present invention.

There are a number of different types of pumps and motors employing arotating cylinder barrel in which the cylinder barrel is suspendedeither on the shaft or in a special bearing located between cylinderbarrel and housing at 'a point in a plane perpendicular to the centerline of the pump at the intersection of pump center line and a planeconnecting spherical piston ends. With the rotary cylinder barrelsuspended at this point, all the transverse moments induced by radialcomponents of piston reaction force are balanced and the cylinder barrelis free to float and alignitself to the face of a stationary valveplate. But in these solutions an anti-friction beara ing of one kind oranother must be introduced. Accordnated. However, a stationary cylinderbarrel requires movable valving means. Movable valving means heretoforeknown in the art, whether of the pintle type or of the type Where aneccentrioally mounted valvingpplate oscillates across a cylinder blockface, are, not of hydrostatically balanced type and either involve theuse of expensive bearings or entail large mechanical losses, thevolumetric and leakage characteristics of these types being inherentlypoor.

It is an object of the present invention to provide simple andinexpensive means for overcoming the above difficulties. I

Another object of the invention is to retain the selfaligning cylinderblock characteristics of usual rotary cylinder barrel design with itsadvantages of high mechanical and volumetric efliciency whileeliminating the parasitic effects of centrifugal force on rotatingpistons by employing a cylinder barrel which is relatively stationary.

Another object is to provide a stationary cylinder barrel pump or motorwith a self-aligning cylinder barrel from which all disturbing forcesare eliminated so it can work at high efliciency level at substantiallyall speeds.

Another object is to provide an improved non-rotating cylinder barreltype of apparatus in which the cylinder barrel is free from transversemoments induced by radial components of hydraulic reaction forces.

Another object is to provide an improved rotating valve plate operablewithout introduction of any disturbing ing to the present invention thefree-floating feature of cylinder barrel is still retained, the cylinderbarrel being free to align itself to the face of rotating valve platebut, at the same time, the great disadvantages of a rotary floatingpoint with associated heavy anti-friction bear in gs is eliminated. i

The deviceshown in the drawings will be described as a motor, althoughit can work just well as a pump. As shown in FIG, 1 a motor body 10 isclosed at one end by a cover 11 secured as by a series of bolts 12. Adriving shaft 16 is provided with internal splines 17 (as for driving aload) and is formed integral with a cam plate 23 which is rotatable withrespect to the housing 10 on anti-friction bearings 24. An inner shaft25 has one end in sliding splined engagement with the cam plate 23 andits other end in sliding splined engagement with the valve plate 26. 1 a

A relatively stationary cylinder barrel 27 works in operationalengagement at one end with the valve plate I 26 and at the other end thebarrel 27 is slide ably and universally mounted by a part-sphericalsurface 28 provided on an annular extension of the cylinder barrel. Thepart-spherical surface 28 of the cylinder barrel is radially located ina sleeve 29 which, in turn, is fixed tudinal bores 33' in which pistons34 are slideably 3 mounted for reciprocation.v The pistons 34 havepartspherical ends 35, and swagged over and thus universally mountedpiston shoes 36 work in contact with the flat face of-the cam plate 123and are axially constrained from leaving this flat surface by anuta-ting plate 38. The piston shoes 36 are hydrostatically balanced ina well-known manner as by each having a recess containing high-pressureoil, and balancing lands thereabout. The high-pressure oil is conductedto the recess by a drilling through each shoe 36 and by'longitudinaldrillings 39 along the center lines of the pistons 34.

The cylinder barrel 27 with its annular extension equipped withpart-spherical surface 28 is universally mounted with respect to thereaction sleeve 29 at a point or along a peripheral line lying in aplane passing through the point of intersection of a plane connectingthe centers of the spherical piston ends 35' with the center line of thecylinder barrel and its coaxial extension.

A compression spring 46 has one end located in a recess provided in thepump body 10 and has its other end engaging a fiat end surface of theannular extension of the cylinder barrel 27.

At the opposite end of the cylinder barrel 27 a flat surface thereofworks in operational contact with the valve plate 26 and is, as is shownin FIG. 4, equipped with a series of kidney-shaped slots 46.sequentially brought into register with the individual slots 46 arevalve plate slots 47 and 68 (see FIGS. 2 and 3).

Slot 47 is a high pressure kidney-shaped opening having a counter-partat the opposite side of the valve plate and these slots communicate withplural axially extending drillings 49 which in turn communicate withradial drillings 56 for establishing communication from the highpressure valve port 47 to a valve plate central cavity 51 and in turnwith a collector ring 52 and a high pressure port 53 which, for motoroperation, is the point at which pressure fluid is introduced to thedevice.

Meanwhile the low pressure valve plate slot 48 communicates throughradial drillings 55 with an annular space within the housing and outsidethe valve plate and cylinder barrel and in turn with a low pressure port56 which, for motor action, takes care of the discharge fluid and forpump action provides the inlet oil.

As will be seen in FIG. 2, the radial drillings 50' may be sealed offwith screw plugs 57 and the central passage 51 may be a drilling latersealed off with a screw plug 53, and the valve plate has a portionjournalled with respect to the housing cover 11 on either side of therotating and stationaryportions of the collector ring 52.

Referring to FIGS. and'6, a modification is shown in which the valveplate is not directly journalled in the end cover 1-1. In FIG. 5, likeparts are like numbered as in FIG. 2, while a central drilling 61terminates at one end in the valve plate flat face adjacent the cylinderbarrel, and at the opposite end terminates in a valve plate flat faceagainst which a balance sleeve 62 works in operational engagement whileheld thereagainst initially by a spring 63 and sealed with respect tothe cover 11 by an O ring 65. A balance cap 66 is connected to abalancing piston 67 by a stem 68 which passes through the cam platecentral drilling 61 and through the balance sleeve 62 which affordscommunication from a space 69 communicating with the high pressure port53. Balancing piston 67 is shown secured to stem 68 by a nut 71 andoperates in a balancing cylinder portion 72 provided in cover 11. Cap 66has a face 73 engaging the flat face of the valve plate. A cam platedrive sleeve 74 is caused to rotate the cam plate through a pin- 75while secured to a driving shaft 76 through a pin 77. At its oppositeend shaft'76 may be provided with a spline for engaging the cam plate.If desired, the piston 67 may be provided with a sealing ring 78 toprevent leakage of high pressure to atmosphere.

Some liberties have been taken in the drawing for reasons of clarity ofdemonstration and those in the art will understand that there willusually be an odd number of pistons, as indicated by the number of slots46 in FIG. 4, and not an even number of pistons, the section of FIG. 1showing pistons at positions of maximum and minimum displacement merelyfor the sake of demonstration, andthe sections i'of FIGS. 2 and 5showing apparently 180 opposite cylinders merely in order to correspondwith FIG. 1.

Operation of the unit The operation of the unit may be described as thatof a high-pressure motor. The housings cylinder barrel mounting sleeve29 acts as a circular reaction ring permanently retained in the pumphousing It). The cylinder barrel 27 with its annular extension equippedwith a part-spherical surface 28 is universally mounted with respect tothis reaction ring 29' preferably at a point or along a peripheral linelying in a plane passing through the point of intersection of a planeconnecting the centers of the spherical piston ends with the center lineof the cylinder barrel and its annular extension. The cylinder barrel 27is prevented from rotation (about its own axis) by pin 36 which engageshole 31 which is made substantially oversize so that it doesnt impairthe freedom of alignment of the cylinder barrel 27. The flat face of thecylinder barrel 27 works in operational contact with a fiat face of thevalve plate 26 which is rotationally connected through the shaft 25 withthe cam plate 26. The cylinder barrel 27 retains the slideable pistons34 which work in operative association, through piston shoes 36, withthe cam plate 23.

In FIGS. 2 and 5 alternative arrangements of valve plate have beenshown, but for the device tooperate as a motor, the arrangement of FIG.5 is preferable,and operation with this arrangement will be theoperation primarily described.

For motor operation, high pressure fluid is introduced through port 53to chamber 69, through sleeve 62, central passage 61, radial drillings50, valve plate kidney slot 47, to passages 46 (for those of thecylinders to be subjected to high pressure), cylinder bores 33, andpistons 34. In FIG- 5, the space 61 is shown closed at one end by thecap 66 and on the other end by the balancing piston 67. The, balancingsleeve 62 Separates the highpressure oil from the low-pressure zonecommunicating through passages 55 ultimately with the low-pressure port56. This construction provides a valve which is free to align itselfwith the flat face of the pump cover and with the flat face of thecylinder barrel, all of the forces resulting from introduction ofhigh-pressure oil to the valve plate being eliminated by balancing. Thusthe pressure acting on balancing piston 67 induces a force carried bythe stem 68 to cap 66 which has a flat surface73 working in operationalcontact with the valve plate, with the eifective area of 73 (dependingon leakage gradient) and the effective area of cap 66 subjected to oiland the effective surface of the balancing piston 67 so selected andarranged that the net force maintains the valve plate in a state ofequilibrium. Areas such as 64 and 73 are so proportioned so that a smallportion of the force supplied, by the piston 67 in the case of area 72,and by the sleeve 62 in the case of area '64, positively maintains thecap 66 and balancing sleeve 62 in contact with the valve plate 26, thussealing the high-pressure oil. The spring 63 anchored at one end to thepump or motor cover and at its other end bearing on a portion of thesleeve 62 maintains the balancing sleeve 62 in contact with the valveplate for starting. Ordinarily the parts 66, 62 and 67 because of themagnitude of sliding forces will remain rotatively stationary, althoughthese parts can rotate without any detrimental effect. All three arefree to slide axially the amount required while the valve plate 26 isdriven from the driving sleeve 74 and shaft 76 and the sleeve 74 by itsengagement with the walls of a central passage 79 in the cylinder barrelmaintains the radial alignment of the valve plate 26.

High-pressure fluid from the port 53 is introduced through the valveplate kidney 47 to the slots 46 leading to the cylinder bores located onone side of the principal axis of the cam plate 23. Such acarnprincipal'axis is an imaginary center line passing along thegreatest'inclination of the cam surface and through its center ofrotation and for the showing of FIG. 1 it may be assumed that the camprincipal axis lies in the plane'of the drawing. Accordingly, pistons toone side of the principal axis of the cam urge their piston shoesagainst the inclined plane of the cam plate and induce a rotary momentin the cam plate which will cause it to revolve while supported by theanti-friction bearings 24 and this rotation will be transmitted throughthe spline shaft 25 or 76 and through sleeve 74 (FIG. to the valve plate26, providing a continuous rotary motion of cam plate while thelow-pressure exhaust oil from cylinders located on the opposite side ofthe cam principal axis is directly discharged to the space 48 of thevalve plate and through drillings 55 to the inside of the pump housingoutside the cylinder barrel and valve plate balancing lands and throughthe low pressure port 56.

Hydraulic reaction acting on the cylinder barrel 27 is transferred tothe valve plate 26 in conventional manner well-known to the art so thatonly a fraction of the total reaction force is transferred to the valveplate as contact pressure. both the port 48 and the kidney-slot 47 onthe front face of the valve plate find their equal equivalents on theback-side of the valve plate. In this Way, the very small forcesnecessary for sealing are carried onlyon the flat faces of the valveplate, the valve plate being maintained in a state of equilibrium.

VJith the arrangement of FIG. 2, however, although the front and backfaces are again balanced, the highpressure oil is introduced from port53 through the col lector ring 52 and through the central passage 51 andradial passages 50, axial drillings 49, and arcuate slots 47, on bothfaces of the valve plate. So that the leakage of pressure around theoutside of the annular extension of the valve plate will not build upand in the end space 59, and thereby cause an unseating of valve plate,this space 59 is preferably ported back to the low-pressure space aroundthe cylinder barrel by means of drillings or piping not shown, except asin FIG. 1.

The cylinder barrel 27 is relatively stationary and is mounted withrespect to the housing on the part-spherical surface 28 in contact withthe ring 29 with these surfaces so positioned, as shown in FIG. 7, thata plane cc through the centers of the spherical piston ends intersectsthe axis aa of the pump or motor at the same point as a plane bbsubstantially through the center of the partspherical surface 28intersects the axis a-a of the pump or motor. Preferably, too, theradius R of the partspherical surface 28 finds its center at this samepoint of intersection of axis of machine with a plane passing throughthe centers of spherical piston ends so that the pistons to one side ofthe vertical have their reaction forces Fr (exerting a clock-wise momentaround the aabb intersection) balanced out by pistons at the other sideof bb exerting a counter-clockwise moment. Thus it is possible to use arelatively stationary cylinder barrel while having transverse componentsof piston reaction forces completely eliminated while the cylinderbarrel is still capable of free-floating for aligning itself against aflat face of the valve plate.

At the same time the geometry of the pump or motor is so arranged thateven with a rotating valve plate and a relatively stationary cylinderbarrel, the latter can freely align itself to the flat face of the valveplate therefore permitting working the device at minimum leakage level.

Free rotation of the cylinder barrel is prevented by the pin 30 which,as shown, engages an oversize hole in the cylinder barrel annularextension.

Since the cylinder barrel 27 is constrained from rotation by the pin 30,the full torque (proportional to the I hydraulic reaction force and theangle of inclination of the cam plate 23) will be transmitted to rotatethe cam It should be observed that in the valve plate plate 23, andtherefore to rotate shaft 25 (or 76) and valve plate 26. V

Thus the whole arrangement is such as to cause a minimum of mechanicaland volumetric losses While permitting the cylinder barrel to alignitself to the valve plate and the valve plate with its balanced backface to carry the reactive loads, while high-pressure oil is introducedthrough the valve plate in such way as to cause no disturbing forceswhich wouldupset this equilibrium, and the advantages usually associatedwith rotating cylinder barrel type pumps are provided in a type of pumphaving a relatively stationary cylinder barrel.

While I have illustrated and described particular em bodiments, variousmodifications may obviously be made without departing-from the truespirit and scope of the invention which I intend to have defined only bythe appended claims taken with all reasonable equivalents.

I claim:

.1. An energy translating fluid pressure device comprising a housing, acylinder barrel substantially non-rotatively positioned in said housing,said cylinder barrel having a central bore, said cylinder barrel havinga plurality of cylindrical bores and pistons reciprocally disposedtherein, a rotary cam plate coactable with said pistons, a rotary valveplate in abutment with one end of said cylinder barrel, said valve plateincluding at least one portwhich sequentially registers with eachcylinder bore, said housing and said cylinder barrel including coactingmeans to permit universal movement therebetween, and

drive means extending through said central bore drivinglyinterconnecting said valve plate and said cam plate, said drive meansslidably engaging at least one of said plates, whereby the axialhydraulic reaction forces on said plates are carried by the housingmember.

2. In a device of claim 1, a pin carried by said housing and a pinabutment surface on said cylinder barrel, said pin being abuttableagainst said pin abutment surface to prevent ro'tative movement betweensaid housing and said barrel and permit universal movement therebetween.

3. In the device of claim 1, said coacting means including an arcuatesurface on said barrel and a c'oacting surface on said housing engagingsaid arcuate surface, said pistons including spherical parts adjacentsaid cam plate, the centers of said spherical parts lying on a planeparallel to the cam plate, said plane of the spherical partsintersecting the axis of the drive means at a point, said point lying ona plane defined by the engagement of said arcuate surface with saidcoacting surface.

4. In the device of claim 1, wherein there is an axially extendingclearance radially between the drive means and the cylinder barrel, andat least one spline drive means interconnecting the cam plate throughthe drive means to the valve plate for driving the valve plate throughsaid clearance to permit freedom of alignment of the parts.

5. A device as in claim 1 further characterized by said drive meansincluding a shaft, the cam plate device being connected to said shaftthrough a spline to permit axial movement of one with respect to theother, a driv ing sleeve connected to rotate with said shaft andradially constrained within the cylinder barrel, and a connectionbetween said sleeve and valve plate to rotatethe valve plate Whileproviding radial location thereof with respect to cylinder barrel.

6. A hydraulic pump or motor device having an outer housing, asubstantially non-rotatable cylinder barrel, a part-spherical surf-aceprovided on one of said parts for universally mounting the barrel withrespect to the housing, pistons arranged for reciprocation in saidcylinder barrel, a rotatable cam plate positioned at one end of saidcylinder barrel, a rotatable valve plate positioned at the opposite endof said cylinder barrel, a shaft connecting the cam plate and the valveplate so that one may effect rotation of the other, said valve platehaving one flat face in contact with the cylinder barrel and an oppositeflat face in contact With a portion of the housing, said valve platehaving kidney-shaped ports disposed equally on the two fiat faces and acentral passage extending between said flat faces, and having radiallyextending passages interconnecting said central passage with thekidney-shaped ports on both faces whereby high-pressure fluid may bereadily transmitted between the central passage and the kidney-shapedports.

7. A device as in claim 6 further characterized by a cap sealing thecentral passage of the valve plate at the end thereof in contact withthe cylinder barrel, a stem. for said cap extending through the valveplate central pas- .sage, and a piston subjected to high pressure andconnected to said stem to urge said cap against said one valve plateface.

8. A device as in claim 7 further characterized by a balancing sleevearranged about said stern and operable against the face of the valveplate in contact With the housing, and means conducting high-pressureoil to force said sleeve against valve plate for sealing the centralpassage with respect to the housing and to cause the pieton to urge thecap against the valve. plate for sealing the central passage at theopposite end.

9. A device as in claim 8 further characterized by the balancing sleeve,piston and cap being configured and arranged so that during normaloperation the balancing sleeve provides against the valve plate a forceequal and opposite to that exerted by the piston and the cap on theopposite side of the valve plate.

10. A device as in claim 9 further characterized by the cap having aface operating against said one face of the valve plate to provide aleakage pressure gradient balancing a portion of the force exerted onthe piston while a small remaining force biases the cap against thevalve plate. 1

11. A device as in claim 10 further characterized by the balancingsleeve having a face in contact with said opposite valve plate face soarranged that a force acting on the cross-section area of the balancingsleeve is counter-balanced by pressure gradient distribution betweensaid faces with a remaining small force maintaining the, sleeve incontact With said opposite valve plate face thus preventing appreciableleakage.

12. A device as in claim 10 further characterized by a compressionspring interposed between the balancing sleeve and a portion of thehousing and for maintaining the sleeve against the valve plate forstarting purposes.

13. A device as in claim 9 further characterized by the housing having ahigh-pressure port leading through a cavity in the housing into acollector ring chamber formed about the cap stem between the sleeve andthe piston.

14. A device as in claim 13 further characterized by the valve platehaving a body extending about a central axis but relieved at one portionto provide substantially direct communication for low-pressure fluid.

15. A device as in claim 14 further characterized by th valve platebeing relieved to provide an arcuate space which communicates with thepistons at low pressure, and the valve plate having an outer ringportion with radial drillings about said space and for providingcommunication with the interior of the housing about the cylinderbarrel, and the housing having a low pressure port communicating withsaid space about the cylinderv barrel.

16. A device as in claim 6 further characterized by the valve platehaving onefiat face adjacent the cylinder barrel and an opposite flatface interrupted by a central cylindrical portion extending beyond saidsecond face and having an internal passage in communication with acollector ring communicating with a high-pressure inlet passing througha portion of the housing, and said valve plate having radial drillingscommunicating between said central passage and arcuate passages in bothfaces.

17. A device as in claim 16 further characterized by the shaft beingsplined at one end to slide with respect to the cam plate and splined atthe other end for making sliding engagement with the valve plate.

References Cited in the file of this patent UNITED STATES PATENTS1,971,601 Dilg Aug. 28, 1934 2,534,153 Widmer Dec. 12, 1950 2,608,159Born Aug. 26, 1952 2,674,197 Dudley Apr. 6, 1954 FOREIGN PATENTS 69,346France May 27, 1958 (1st addition to No. 1,146,899) 1,120,346 FranceApr. 16, 1956

